Relationship between the abnormal diastolic vortex structure and impaired left ventricle filling in patients with hyperthyroidism

Abstract

Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex and left ventricular (LV) filling is still rarely elucidated. The aim of this study was to evaluate the evolution of vortex during diastole in hyperthyroidism (HT) and explore the alteration of hydromechanics characteristics with sensitive indexes.Forty-three patients diagnosed with HT were classified into 2 groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22). Twenty-seven age- and gender-matched healthy volunteers were enrolled as the control group. Offline vector flow mapping (VFM model) was used to analyze the LV diastolic blood flow patterns and fluid dynamics. Hemodynamic parameters, vortex area (A), circulation (C), and intraventricular pressure gradient (ΔP), in different diastolic phases (early, mid, and late) were calculated and analyzed.HT2, with a lower E/A ratio and left ventricular ejection fraction (LVEF), had a larger left atrium diameter (LAD) compared with those of the control group and HT1 (P < .05). Compared with the control group, the vortex size and strength, intraventricular pressure gradient during early and mid-diastole were higher in HT1 and lower in HT2 (P < .05). And in late diastole, the vortex size and strength, intraventricular pressure gradient of HT2 became higher than those of the control group (P < .05). Good correlation could be found between CE and E/A (P < .05), CM and ΔPM (P < .01), CL and FT3 (P < .05).VFM is proven practical for detecting the relationship between the changes of left ventricular diastolic vortex and the abnormal left ventricular filling.

Conflict of interest statement

The authors have no conflicts of interest to disclose.

Figures

Figure 1

Formation and evolution of the intraventricular vortex during diastole. Vortex features displayed a typical biphasic temporal course during diastole in all 3 groups. Two vortexes appeared behind the MV leaflets during early diastole (A1, B1, and C1), and the posterior vortex in HT2 (C1) failed to be detected in an unstable condition. In mid-diastole, a relatively apically located large vortex existed in the control group and HT1 (A2, B2). Instead, several small and scattered vortexes appeared in HT2 (C2). Like early diastole, 2 symmetric vortexes appeared below MV in late diastole (A3, B3, and C3).

Figure 2

Evolvement of circulation in different diastolic phases. In early diastole, circulation of controls was weaker than those of HT1 and stronger than those of HT2. Circulation of these 3 groups increased in mid diastole concurrently. During the end of diastole, circulation in HT2 developed higher than the control group but still below HT1. The differences among the 3 groups were significant (P < .05).

Figure 3

Bland–Altman plots of intraobserver (left) and interobserver (right) showing variability of diastolic ΔP and circulation. Average values of the measurements are plotted against the difference in the measurements. The arithmetic mean (continuous line) and 95% limits of agreement (equal to ± 1.96 SD; dotted lines) are determined.